The present invention relates generally to optical waveguide devices, semiconductor lasers, solid state lasers, and particularly to the utilization of lasers to pump optical waveguide amplifiers.
Optical amplifiers and lasers are important components used in optical fiber telecommunications systems. Optical signals transmitted in optical fibers tend to weaken as they travel along the optical fibers. Optical amplifiers provide an economic means of amplifying such weakened optical signals while maintaining the optical nature of the signal.
Erbium doped optical fiber amplifiers have become the dominant means of amplifying optical signals in the 1550 nm optical telecommunications window. Such erbium doped optical fiber amplifiers are normally directly pumped with 980 nm and/or 1480 nm semiconductor pump lasers. With such an amplifier-pump system, electrical energy applied to the 980 nm (1480 nm) semiconductor pump laser produces 980 nm (1480 nm) photons which are coupled through an optical fiber pigtail into the erbium doped optical fiber. The 980 nm and/or 1480 nm pump light excites/energizes the erbium ions in the erbium doped optical fiber so that 1550 nm optical telecommunications signals are amplified by the excited/energized erbium ions. Such direct optical pumping of optical amplifiers with semiconductor produced photons has become the standard in the optical telecommunications industry because of reliability and related use requirements, for example compact space utilization. But, in addition to economic expense problems, such direct semiconductor pump lasers pose problems in terms of already reaching maximum optical output power limitations while the development of optical amplifiers has continued to require higher and higher pump power input requirements. It appears that the commercially available maximum reliable output power of 980 nm semiconductor laser pumps may plateau in the 300 mW output power range while the input pump power requirements of optical amplifiers continue to climb. Semiconductor laser research and development continue to strive towards improving the structure and performance of 980 nm semiconductor laser pumps in an effort to try to meet the needs of optical amplifiers.
The optical amplifier industry needs a pump laser technology that is able to meet its ever increasing optical power demands.
One aspect of the present invention is an optical waveguide device which includes a solid state laser which outputs wavelength emission xcexss centered about 946 nm, combined with a lasing waveguide which includes a Yb doped optical waveguide such that when the xcexss output is inputted into the lasing waveguide the lasing waveguide produces a wavelength emission xcexy centered about 980 nm.
In another aspect, the present invention includes a method of producing 980 nm optical amplifier pump wavelength light which includes providing a first laser for producing an emission xcex1, inputting the produced emission xcex1 into a second laser for producing an emission xcex2, producing an emission xcex2, inputting the produced emission xcex2 into a third laser for producing an emission xcex3 centered about the 980 nm optical amplifier pump wavelength.
In a further aspect the invention includes an optical amplifier device which includes at least one semiconductor laser which produces an emission xcex1, centered about 808 nm, a first solid state laser which is optically pumped by the semiconductor laser such that it produces an emission xcex2 centered about 946 nm, a second solid state laser which is optically pumped by the first solid state laser such that it produces an emission xcex3 centered about 980 nm, and an optical amplifier waveguide for amplifying an optical transmission signal wherein the optical amplifier is optically pumped by the second solid state laser.
The invention further includes a method of amplifying an optical transmission signal which comprises the steps of: providing a first laser for producing xcex1 light, a second laser for producing xcex2 light, and a third laser for producing xcex3 light, and an optical amplifier which utilizes xcex3 light to amplify an optical signal; pumping the second laser with xcex1 light produced by the first laser; pumping the third laser with xcex2 light produced by the second laser; and pumping the optical amplifier with xcex3 light produced by the third laser.
Additionally, the invention includes a method of making a 980 nm pump for an optical amplifier, with the method including: providing at least one semiconductor laser diode, coupling the semiconductor laser diode into a Nd:YAG laser, and coupling the Nd:YAG laser into a Yb doped optical waveguide fiber laser.
In a further aspect the invention includes an optical amplifier system comprising a single cladding optical waveguide lasing fiber and a multimode pump source.
The invention further comprises a method of making an optical amplifier pump, which includes providing a multimode pump source; providing a single cladding optical waveguide lasing fiber; and indirectly pumping the lasing fiber with the multimode pump source.
Additionally the invention includes the method of amplifying an optical signal xcext, by providing a multimode light pump source having a wavelength xcexmm multimode brightness output; converting the multimode brightness output into a single mode output having a wavelength xcexpump; and inputting the single mode output into an optical amplifier for amplifying an optical signal xcext.
In a further aspect the invention includes an optical amplifier pump for pumping an optical amplifier with a pump wavelength xcexpump, where the pump includes a semiconductor laser which produces a wavelength xcexsemi and the pump outputs at least 500 mW of light at xcexpump.
Additionally the invention includes an optical amplifier pump comprising: a semiconductor laser which produces a wavelength xcex1 for pumping Nd ions; a plurality of Nd ions, which when pumped by the wavelength xcex1, produces a wavelength xcex2 for pumping Yb ions; and a plurality of Yb ions, which when pumped by the wavelength xcex2 produces a wavelength xcex3 for pumping Er ions.
In a further aspect the invention includes an optical amplifier pump for pumping an optical amplifier which amplifies optical signals in the range of 1560 to 1620 nm (L-band), which has at least one broad area semiconductor laser; and a neodymium doped solid state laser, with solid state laser pumped by the semiconductor laser.
Additionally the invention includes an optical amplifier that comprises a semiconductor laser; a solid state laser, the solid state laser pumped by the semiconductor laser; and an Er doped optical amplifier fiber, with the Er doped optical amplifier fiber for amplifying signals in the range of 1560 to 1620 nm and pumped by the solid state laser.
In a further aspect the invention includes a method of amplifying a L-band optical signal by providing an Er doped optical fiber, pumping a neodymium solid state laser with a broad area semiconductor laser, inputting said solid state laser directly into the Er doped optical fiber, and amplifying a L-band optical signal with the Er doped optical fiber.
Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operation of the invention.